LONDON – Britain’s Serious Fraud Office is charging three former employees of broker ICAP PLC in the scandal related to the rigging of a key market interest rate.

Criminal proceedings began Friday against Danny Martin Wilkinson, Darrell Paul Read and Colin John Goodman in the manipulation of the London interbank offered rate, or LIBOR.

The fraud office said the charges against the brokers stemmed from alleged manipulation of the Yen LIBOR — the Japanese yen version of the benchmark rate. The SFO alleges they conspired to defraud between Aug. 8, 2006 and Sept. 7, 2010.

Westminster Magistrates’ Court will hear pleas on April 15.

With Friday’s action, nine people have been implicated in the investigation of LIBOR, the rate used by banks to borrow from each other. The influential benchmark indirectly affects the cost of loans throughout the economy.

U.S. and British regulators have been working together on LIBOR prosecutions.